Microstructural evolution of low carbon Cr-Mo steel tempered by induction heating

Microstructural evolution of a low alloy steel tempered at various temperature in the range of 300-700 degree C using induction heating method was examined. A series of microstructural evolution such as precipitation of acicular cementite with particular orientation and formation of spheroidized cementite was observed with increasing tempering temperature. Comparing to the tempered steel with salt-bath, similar tempered microstructure could be obtained at higher temperature by induction heating. Tensile stress-strain curves of the tempered steel revealed that the excellent formability of the low alloy steel would be achieved by tempering in the range of 500-700 degree C with induction heating method which is commercially applicable heat-treatment process